AD 77-16-07
Applicability
| Type | Manufacturer | Model | Details |
|---|---|---|---|
| aircraft | Airbus Helicopters Deutschland GmbH | BO-105A | Airworthiness Directives; Messerschmitt-Bolkow-Blohm (MBB) Model BO-105A and BO-105C Helicopters |
| aircraft | Airbus Helicopters Deutschland GmbH | BO-105C | Airworthiness Directives; Messerschmitt-Bolkow-Blohm (MBB) Model BO-105A and BO-105C Helicopters |
Unsafe Condition
Excessive wear of the sun gear in the planet gear carrier of the main rotor gearbox due to inadequate lubrication from the main rotor gearbox oil pumps with part numbers 7631 955 112 or 7631 955 115.
AI-generated summary from the source AD text. Verify against the official source before acting.
Required Actions
Within 100 hours time in service after the effective date, modify the main rotor gearbox oil pump by installing a stronger compression spring (per MBB SB No. 10-16) for P/N 7631 955 115, and replace the pump plunger and install a stronger spring (per MBB SB No. 10-20 and 10-16) for P/N 7631 955 112. Additionally, inspect the magnetic chip detector plug every 10 hours time in service for metallic particles, following MBB instructions if found.
AI-generated summary from the source AD text. Verify against the official source before acting.
Compliance Time
Within the next 100 hours time in service after the effective date of this AD, and within the next 10 hours time in service after the effective date and thereafter at intervals not to exceed 10 hours time in service since the last inspection.
AI-generated summary from the source AD text. Verify against the official source before acting.
Affected Aircraft
Messerschmitt-Bolkow-Blohm (MBB) Model BO-105A and BO-105C helicopters with main rotor gearbox oil pumps P/N 7631 955 112 or 7631 955 115, having Serial Numbers up to and including 229.
AI-generated summary from the source AD text. Verify against the official source before acting.
Source: Official FAA Source ↗
Retrieved: Apr 8, 2026
Rights: U.S. Government Public Domain
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